Nervous System II
lumbar region of the back into the pelvic cavity, giving rise
to a number of motor and sensory F
bers associated with the
lower abdominal wall, external genitalia, buttocks, thighs,
legs, and feet. The major branches of these plexuses include
(f g. 11.34)
supply the adductor muscles of the
divide into many branches,
supplying motor impulses to muscles of the anterior
thighs and receiving sensory impulses from the skin of
the thighs and legs.
are the largest and longest nerves in
the body. They pass downward into the buttocks and
descend into the thighs, where they divide into
The many branches of these
nerves supply muscles and skin in the thighs, legs, and
Nerves of the lumbosacral plexus. (
) Close up. (
)Anterior view. (
) Posterior view.
Other nerves associated with the lumbosacral plexus that
innervate various skeletal muscles include the following:
supplies the muscles of the perineum.
superior gluteal nerves
gluteal muscles and the tensor fasciae latae muscle.
The ventral branches of the thoracic spinal nerves do not
enter a plexus. Instead, they travel into spaces between the
ribs and become
nerves supply motor impulses to the intercostal muscles and
the upper abdominal wall muscles. They also receive sensory
impulses from the skin of the thorax and abdomen. Clinical
Application 11.7 discusses injuries to the spinal nerves.
How are spinal nerves grouped?
Describe how a spinal nerve emerges from the spinal cord.
Name and locate the major nerve plexuses.